Why Is Moss Growing on My Roof? (and What To Do About It)

Many homeowners in the Seattle, Tacoma, or Bellevue area experience Roof Moss and Algae. While it makes our forests beautiful, it’s not good for your roof. Most people are unaware of how destructive the plants can be to their roof.

The short video will show you what Roof Moss and Algae can do,

Why are algae and moss growing on my roof?

Moss and algae thrive in cool, damp environments. If you have moss on your roof, it’s likely because your roof is shaded by trees or other structures, allowing moisture to linger and moss to grow. If your roof is not kept clean and well-maintained, roof moss and algae can shave years off the life of your roof.

Algae is the black staining that you see on roofs. Moss, the green fluffy stuff you see on the roof, feeds on the algae. And when you add tree debris, like needles and leaves, then these moisture issues can be compounded. Not only does moss and algae look bad, but they are also very destructive.

Moss is a non-vascular plant that absorbs water through its leaves instead of roots. Its seeds, called spores, are tiny one-celled reproductive units that become air-borne and make their way onto roofs through wind, birds, squirrels, and other small animals. Once the spores get on the roof, they gather in the spaces between shingles and grow into thick spongy moss. The tiny moss roots dig into your roof and the roof granule surfacing is compromised. This makes the roof vulnerable to UV degradation. This reduces the roof life. And when it creeps under the roofing material, it breaks the seal which makes it vulnerable to wind damage. 

Since moss thrives in damp environments, areas of the roof that get the least amount of direct sunlight, like north-facing sections or areas shaded by tree limbs, make an ideal place for it to grow. Once moss establishes itself, it absorbs rainwater like a sponge and can spread across the entire roof and grow a few inches thick. 

How To Treat Moss and Algae

There are some common methods to treat areas that have algae and moss, but they aren’t very effective. One is to use a zinc strip. Zinc does kill moss, but typically only for a few feet down the roof and only for a limited time. You also have to nail through the roof to install the zinc strip, which further damages your roof. Another treatment is to use a zinc or chlorine-based detergent on the roof. These are corrosive chemicals that are bad for the environment and don’t prevent the algae and moss from regrowing. Pressure washing also damages or even destroys the roof.

So, we’ve developed the Guardian Solution. We start with a professional consultation and diagnosis. Then we use our gentle process to remove the big moss and debris from your roof, which exposes the algae. We then apply our environmentally safe algae loosening solution and gently rinse away the leftover debris leaving a clean and safe roof. Our process works for asphalt composite, concrete tile, and wood shake. And of course, it does make a big mess while the job is being done, but don’t fret, our professional technicians thoroughly clean up before they leave.

Guardian Roofing recommends asking for our free roof inspection. Our expert tile roof inspector will determine if your roof is at risk. If your roof is in need of maintenance, we’ll use our gentle process of air and light rinsing to get the roof and water channels clean. So, if you have moss and algae issues, give us a call at 877-926-9966, or schedule a free inspection online.